It is known to provide RF sending units on vehicle wheels that provide information to a central radio receiver and processor on the vehicle about the status of the wheel, e.g., the wheel identity number (ID), the wheel location, whether it is rolling or stationary, wheel temperature, tire pressure, and so forth. Such systems are described for example in U.S. Pat. No. 5,109,213 to Williams; U.S. Pat. No. 6,441,728 B1 to Dixit et al, U.S. Pat. No. 6,486,773 B1 to Baille et al, U.S. Pat. No. 6,518,876 B1 to Marguet et al and U.S. Pat. No. 6,580,365 B2 to Starkey.
FIG. 1 is a simplified schematic diagram of prior art system 9 comprising five vehicles wheels 10A–10E interacting with on-board data receiver 14. Each vehicle wheel 10A–10E, has transmitter or sender 11A–11E coupled to instrumentation package 13A–13E and to antenna 12A–12E. Instrumentation package 13A–13E provides wheel ID, location and status information that is sent via RF signal 18A–18E from sender 11A–11E via antenna 12A–12E to on-board receiver 14 via antenna 15. Depending upon the particular approach used for correlating wheel ID and wheel location, signals 18A–18E may be bi-directional and/or encompass location transmitters or transceivers in the wheel wells, but this is not important to the present invention. Such systems are well known in the art and described, for example, in the above-referenced patents.
In many cases, these systems have two modes of operation: (1) a learning mode in which the wheel mounted unit interacts with a vehicle mounted location unit so that information on the tire ID and location on the vehicle can be related and learned by the vehicle electronics system so that it knows which wheel is where on the vehicle, and (2) an operating mode where the individual wheel sending unit transmits or sends its ID, location and status (e.g., rolling, temperature, pressure, etc.). In many arrangements the learning mode is only infrequently invoked, for example, when the wheels are mounted on the vehicle at the factory or when the wheels are rotated at a service location and the service technician accesses the vehicle diagnostic system to re-invoke the learning mode. In this situation, wheel location information stored in the on-board vehicle system memory remains unchanged until the learning mode is invoked again. A weakness of this arrangement is that when an unexpected tire change is made (e.g., when a flat occurs) the information stored in the central electronics unit is no longer current.
Accordingly, it is desirable to provide a system for detecting that a wheel change has taken place and updating the wheel ID and location information in the on-board vehicle electronics system memory without having to re-invoke the learning mode. In addition, it is desirable to be able to accomplish this without additional hardware and/or modification of the wheel mounted or vehicle mounted sensors, detectors, transmitters, receivers, ID units, and so forth. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.